using System;

public class Program

{

    public static void Main()

    {

        int num,counter=0;

        for (int i=1; i<=20; i++)

        {

            Console.WriteLine("enter number");

            num=int.Parse(Console.ReadLine());

            if (num>=10 && num<=99)

            {

                if (num%2==0)

                {

                    counter++;

                }

            }

        }

            Console.WriteLine(counter);

    }

}